Religiosity and Substance Use Disorder in Kenya: What are the Implications on the Future of Rehabilitation Interventions?

Substance use is increasingly becoming a global problem and a constant health crisis that affects each region of the world. Substance use tends to induce certain disorders and this makes users prone to psychological disorders such as depression, anxiety and psychosis among others. Successful treatment for substance use disorders (SUD) must take into account other underlying factors that either protect or predispose the patients to SUD. Religiosity has been suggested as one of the most important protective factors against drug use, preventing individuals from using drugs even if they live in precarious environments. However, previous studies in Kenya have not investigated the links between religiosity and substance use disorder in the country prompting the need for the study. The study adopted a quasi-experimental design targeting 6 government accredited rehabilitation centers in Kenya. A sample size of 120 participants were selected through convenience sampling. The Socio-Demographic Questionnaire and substance use assessment tools consisting of the Alcohol Use Disorders Identification Test (AUDIT) and the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) were used for data collection. Quantitative data generated was analyzed using descriptive and inferential statistics involving frequency distributions, percentages and chi-square respectively. The study found that religion was a significant risk factor rather than a protective factor among persons with SUD in Kenya including some who had already undergone treatment. The study recommends that the religious message in the rehabilitation programs should seek to reinforce behaviour through engendering factual understanding of one’s behaviours and their spiritual realities

Integration of crosswind forces into train dynamic modelling

In this paper a new method is used to calculate unsteady wind loadings acting on a railway vehicle. The method takes input data from wind tunnel testing or from computational fluid dynamics simulations (one example of each is presented in this article), for aerodynamic force and moment coefficients and combines these with fluctuating wind velocity time histories and train speed to produce wind force time histories on the train. This method is fast and efficient and this has allowed the wind forces to be applied to a vehicle dynamics simulation for a long length of track. Two typical vehicles (one passenger, one freight) have been modelled using the vehicle dynamics simulation package ‘VAMPIRE®’, which allows detailed modelling of the vehicle suspension and wheel—rail contact. The aerodynamic coefficients of the passenger train have been obtained from wind tunnel tests while those of the freight train have been obtained through fluid dynamic computations using large-eddy simulation. Wind loadings were calculated for the same vehicles for a range of average wind speeds and applied to the vehicle models using a user routine within the VAMPIRE package. Track irregularities measured by a track recording coach for a 40 km section of the main line route from London to King's Lynn were used as input to the vehicle simulations. The simulated vehicle behaviour was assessed against two key indicators for derailment; the Y/Q ratio, which is an indicator of wheel climb derailment, and the Δ Q/Q value, which indicates wheel unloading and therefore potential roll over. The results show that vehicle derailment by either indicator is not predicted for either vehicle for any mean wind speed up to 20 m/s (with consequent gusts up to around 30 m/s). At a higher mean wind speed of 25 m/s derailment is predicted for the passenger vehicle and the unladen freight vehicle (but not for the laden freight vehicle)

A semi-implicit, second-order-accurate numerical model for multiphase underexpanded volcanic jets

Abstract. An improved version of the PDAC (Pyroclastic Dispersal Analysis Code, Esposti Ongaro et al., 2007) numerical model for the simulation of multiphase volcanic flows is presented and validated for the simulation of multiphase volcanic jets in supersonic regimes. The present version of PDAC includes second-order time- and space discretizations and fully multidimensional advection discretizations in order to reduce numerical diffusion and enhance the accuracy of the original model. The model is tested on the problem of jet decompression in both two and three dimensions. For homogeneous jets, numerical results are consistent with experimental results at the laboratory scale (Lewis and Carlson, 1964). For nonequilibrium gas–particle jets, we consider monodisperse and bidisperse mixtures, and we quantify nonequilibrium effects in terms of the ratio between the particle relaxation time and a characteristic jet timescale. For coarse particles and low particle load, numerical simulations well reproduce laboratory experiments and numerical simulations carried out with an Eulerian–Lagrangian model (Sommerfeld, 1993). At the volcanic scale, we consider steady-state conditions associated with the development of Vulcanian and sub-Plinian eruptions. For the finest particles produced in these regimes, we demonstrate that the solid phase is in mechanical and thermal equilibrium with the gas phase and that the jet decompression structure is well described by a pseudogas model (Ogden et al., 2008). Coarse particles, on the other hand, display significant nonequilibrium effects, which associated with their larger relaxation time. Deviations from the equilibrium regime, with maximum velocity and temperature differences on the order of 150 m s−1 and 80 K across shock waves, occur especially during the rapid acceleration phases, and are able to modify substantially the jet dynamics with respect to the homogeneous case

Change and continuity at PPA

This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this record.In June 2017, Public Policy and Administration (PPA) received its first Impact Factor of 1.529 in 2016 Journal Citation Reports®. It is a fantastic score, even more so considering this has been the very first year the journal was included in the index. As a result, PPA is now ranked 19/47 in the field ‘Public Administration’! This is major change for PPA, which this year celebrates its 30th year, and bodes very well for its future. And so, we want to take this opportunity to send a strong message of continuity to our readership and all the prospective contributors. [...

Insights into the formation and dynamics of coignimbrite plumes from one-dimensional models

Coignimbrite plumes provide a common and effective mechanism by which large volumes of fine-grained ash are injected into the atmosphere. Nevertheless, controls on formation of these plumes as a function of eruptive conditions are still poorly constrained. Herein, two 1-D axysymmetric steady state models were coupled, the first describing the parent pyroclastic density current and the second describing plume rise. Global sensitivity analysis is applied to investigate controls on coignimbrite plume formation and describe coignimbrite source and the maximum plume height attained. For a range of initial mass flow rates between 108 and 1010 kg/s, modeled liftoff distance (the distance at which neutral buoyancy is attained), assuming radial supercritical flow, is controlled by the initial flow radius, gas mass fraction, flow thickness, and temperature. The predicted decrease in median grain size between flow initiation and plume liftoff is negligible. Calculated initial plume vertical velocities, assuming uniform liftoff velocity over the pyroclastic density current invasion area, are much greater (several tens of m/s) than those previously used in modeling coignimbrite plumes (1 m/s). Such velocities are inconsistent with the fine grain size of particles lofted into coignimbrite plumes, highlighting an unavailability of large clasts, possibly due to particle segregation within the flow, prior to plume formation. Source radius and initial vertical velocity have the largest effect on maximum plume height, closely followed by initial temperature. Modeled plume heights are between 25 and 47 km, comparable with Plinian eruption columns, highlighting the potential of such events for distributing fine-grained ash over significant areas

Distributional pattern of Sardinian orchids under a climate change scenario

The Mediterranean is one of the major biodiversity hotspots of the world. It has been identified as the “core” of the speciation process for many groups of organisms. It hosts an impressive number of species, many of which are classified as endangered taxa. Climate change in such a diverse context could heavily influence community composition, reducing ecosystems resistance and resilience. This study aims at depicting the distribution of nine orchid species in the island of Sardinia (Italy), and at forecasting their future distribution in consequence of climate change. The models were produced by following an “ensemble” approach. We analysed present and future (2070) niche for the nine species, using Land Use and Soil Type, as well as 8 bioclimatic variables as predictors, selected because of their influence on the fitness of these orchids. Climate change in the next years, at Mediterranean latitudes, is predicted to results mainly in an increase of temperature and a decrease of precipitation. In 2070, the general trend for almost all modelled taxa is the widening of the suitable areas. However, not always the newly gained areas have high probability of presence. A correct interpretation of environmental changes is needed for developing effective conservation strategies

Il progetto EPLORIS: La ricostruzione virtuale dell'eruzione del Vesuvio

The main objective of the Exploris project consists in the quantitative analysis of explosive eruption risk in densely populated EU volcanic regions and the evaluation of the likely effectiveness of possible mitigation measures through the development of volcanic risk facilities (such as supercomputer models, vulnerability databases, and probabilistic risk assessment protocols) and their application to high-risk European volcanoes. Exploris’ main ambition is to make a significant step forward in the assessment of explosive eruption risk in highly populated EU cities and islands. For this project, a new simulation model, based on fundamental transport laws to describe the 4D (3D spatial co-ordinates plus time) multiphase flow dynamics of explosive eruptions has been developed and parallelized in INGV and CINECA. Moreover, CINECA developed specific tools to efficiently visualise the results of simulations. This article presents the results of the large numerical simulations, carred out with CINECA’s Supercomputers, to describe the collapse of the volcanic eruption column and the propagation of pyroclastic density currents, for selected medium scale (sub-Plinian) eruptive scenarios at Vesuvius

An application of parallel computing to the simulation of volcanic eruptions

A parallel code for the simulation of the transient 3D dispersal of volcanic particles produced by explosive eruptions is presented. The model transport equations, based on the multiphase flow theory, describe the atmospheric dynamics of the gas-particle mixture ejected through the volcanic crater. The numerics is based on a finite-volume discretization scheme and a pressure-based iterative non-linear solver suited to compressible multiphase flows. The code has been parallelized by adopting an ad hoc domain partitioning scheme that enforces the load balancing. An optimized communication layer has been built over the Message-Passing Interface. The code proved to be remarkably efficient on several high-performance platforms and makes it possible to simulate fully 3D eruptive scenarios on realistic volcano topography

Neutron spectrometry at various altitudes in atmosphere by passive detector technique

A new experimental system, constituted by passive detectors, has been developed to measure neutron spectra at various altitudes in the atmosphere. The knowledge of the neutron spectrum is required to evaluate with a good accuracy the neutron contribution to the total dose, due to the cosmic ray exposure, in fact the flux-to-dose conversion factors strongly depend on neutron energy. Moreover, in many dosimetric applications, as the dose evaluation to the aircrew in service on intercontinental flights, the passive system is not only the most convenient but it is often the unique technique. The experimental system is constituted by the passive bubble detector BD100R, polycarbonate foils, polycarbonate bottles, sensitive in low and intermediate neutron energy range, and the bismuth stack, sensitive in the high energy range. Experimental data were obtained in high mountain measurements at Matterhorn (3600 m altitude, 46 N ) and Chacaltaya (5230 m altitude, 16 S), during flights at 12000 m and on board of stratospheric balloons at 38000 m. All the spectra obtained show, as expected, the evaporation peak around 1 MeV and the second direct bump around 100 MeV; the results, different in the neutron flux intensity, confirm the satisfactory sensitivity of this experimental technique

Large-eddy simulation of pyroclastic density currents

We investigate the dynamics of turbulent pyroclastic density currents (PDCs) by adopting a 3D, Eulerian-Eulerian multiphase flow model, in which solid particles are treated as a continuum and the grain-size distribution is simplified by assuming two particulate phases. The turbulent sub-grid stress of the gas phase is modelled within the framework of Large-Eddy Simulation (LES) by means of a eddy-viscosity model together with a wall closure. Despite the significant numerical diffusion associated to the upwind method adopted for the Finite-Volume discretization, numerical simulations demonstrate the need of adopting a Sub-Grid Scale (SGS) model, while revealing the complex interplay between the grid and the SGS filter sizes. We also analyse the relationship between the averaged flow dynamic pressure and the action exerted by the PDC on a cubic obstacle, to evaluate the impact of a PDC on a building. Numerical results suggest that the average flow dynamic pressure can be used as a proxy for the force per unit surface acting on the building envelope (Fig. 5), even for such steeply stratified flows. However, it is not possible to express such roportionality as a constant coefficient such as the drag coefficient in a steady-state current. The present results indeed indicate that the large epistemic and aleatory uncertainty on initial and boundary conditions has an impact on the numerical redictions which is comparable to that of grid resolution